The present invention relates to a method, and also to a system, for monitoring certain actions of ruminant animals in order to provide an indication of the physiological condition of the animal, a possible health problem in the animal, the suitability of the animal feed, and/or the suitability of the animal for continued milk production. The invention is particularly useful for monitoring dairy cattle to optimize the cattle feed for milk production and animal health, and the invention is therefore described below with respect to this application.
Ruminant animals, such as cattle, have a stomach divided into a plurality of chambers, the first of which is called the rumen. The animal ingests relatively large amounts of feed into the rumen with a minimum of chewing (a cud), before swallowing, periodically regurgitates a portion of the contents of the rumen (in the form of a bolus) back into the mouth, and further chews the regurgitated portion (bolus) before it is again swallowed and then directed to the other chambers of the stomach where it is further digested with the aid of various micro-organisms in the stomach.
It is well known that the content of the animal feed is an important factor in producing maximum milk production in milking cows, and optimum health in both milking cows and dry cows. Thus, fiber and roughage in the animal's diet stimulates fiber rumination, chewing, and saliva production, all necessary for maximum milk production in milking animals and optimum animal health. Inadequate fiber or roughage in the animal diet decreases chewing, rumination, and saliva such as to decrease milk production and to endanger animal health. Saliva produced by the animal during rumination introduces a bicarbonate which acts to buffer the rumen against acids. Sufficient rumination is also necessary to maintain a functional fiber mat in the rumen, which is important for the prevention of abomasal displacement, ketosis, retained placenta, and other diseases associated with low fiber/acidosis like laminitis, particularly in dry and postpartom cows. Therefore insufficient rumination may produce metabolic problems in the animal, such as acidosis, sore feet and off-feet problems; a decreased fat content of the milk; and/or an inadequate fiber mat in the rumen of dry animals for the prevention of abomasal displacement.
On the other hand, excessive fiber content or roughage in the animal feed limits the intake and digestibility, and therefore tends to reduce milk production.
In general, cows should be chewing their cuds about 50% of the time when not being fed or moved or milked, to produce adequate rumination activities. Also, a failure to chew for a continuous period of 2 or 3 hours would indicate a health problem.